SUN Shi-jun1, DING Yue-yuan2, CAO bO2, TIAN yuan3
(1.Institute of Applied Ecology, CAS, Shenyang 110016, China;
2.Beijing Hydraulic Research Institute, Beijing 100044, China;
3.Beijing Post-Graduate School, North China Hydraulic and Hydro-electric College, Beijing 100044, China)
Abstract: Since the 1980s, because of scarcy precipitation in northern China, the level of farmland groundwater has been decreasing and the storage capacity of soil risen accordingly. According to the information observed from the experimental site of water resources to the south-east plain of Beijing, the 0—3m layer soil was determined as the defined depth of soil reservoir and its pondage capacity was analyzed. Through computation it was found out that, before the rainy season during 1991—1995, the normal annual available pondage capacity of soil reservoir was 137.4mm (0—2m depth) and 188.8mm (0—3m depth) respectively. The results showed that soil reservoir had very good regulation capacity and 85% of the normal annual precipitation was stored in the 3m deep soil (the defined depth of soil reservoir). So if some available measures are taken before an extraordinary rainstorm happens, then there will be no or less surface runoff appearing and most of the precipitation will be stored in soils.
Keywords: well irrigation fields; soil reservoir; precipitation and runoff; pondage capacity
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